Display screen or portion thereof with a graphical user interface



FIG. 1 is a front view of a first image in a sequence of a displayscreen or portion thereof with a graphical user interface, showing thenew design; and,

FIG. 2 is a front view of a second image thereof, shown without thebroken line environment for clarity of disclosure.

The appearance of the animated image sequentially transitions betweenthe images shown in FIGS. 1 through 2. This process or period in whichone image transitions to another forms no part of the claimed design.

The outermost broken lines in FIG. 1 illustrate the environment of thedesign and form no part of the claim. The remaining broken lines,including all text, illustrate portions of the display screen orportions of the graphical user interface that form no part of theclaimed design.

CLAIM The ornamental design for a display screen or portion thereof witha graphical user interface, as shown and described.